chore: 🤖 make parking_lot dependency optional

Cargo.toml

@@ -19,15 +19,15 @@ name = "string_cache"
 
 [features]
 serde_support = ["serde"]
-default = ["serde_support"]
-
+default = ["serde_support", "parking_lot_support"]
+parking_lot_support = ["parking_lot"]
 [dependencies]
 precomputed-hash = "0.1"
 once_cell = "1.10.0"
 serde = { version = "1", optional = true }
 phf_shared = "0.10"
 new_debug_unreachable = "1.0.2"
-parking_lot = "0.12"
+parking_lot = { version = "0.12", optional = true}
 
 [[test]]
 name = "small-stack"

src/atom.rs

@@ -200,8 +200,13 @@ impl<'a, Static: StaticAtomSet> From<Cow<'a, str>> for Atom<Static> {
                     phantom: PhantomData,
                 }
             } else {
+                #[cfg(feature = "parking_lot_support")]
                 let ptr: std::ptr::NonNull<Entry> =
                     DYNAMIC_SET.lock().insert(string_to_add, hash.g);
+
+                #[cfg(not(feature = "parking_lot_support"))]
+                let ptr: std::ptr::NonNull<Entry> =
+                    DYNAMIC_SET.lock().unwrap().insert(string_to_add, hash.g);
                 let data = ptr.as_ptr() as u64;
                 debug_assert!(0 == data & TAG_MASK);
                 Atom {
@@ -237,6 +242,12 @@ impl<Static> Drop for Atom<Static> {
 
         // Out of line to guide inlining.
         fn drop_slow<Static>(this: &mut Atom<Static>) {
+            #[cfg(not(feature = "parking_lot_support"))]
+            DYNAMIC_SET
+                .lock()
+                .unwrap()
+                .remove(this.unsafe_data.get() as *mut Entry);
+            #[cfg(feature = "parking_lot_support")]
             DYNAMIC_SET
                 .lock()
                 .remove(this.unsafe_data.get() as *mut Entry);

src/dynamic_set.rs

@@ -8,12 +8,15 @@
 // except according to those terms.
 
 use once_cell::sync::Lazy;
+#[cfg(feature = "parking_lot_support")]
 use parking_lot::Mutex;
 use std::borrow::Cow;
 use std::mem;
 use std::ptr::NonNull;
 use std::sync::atomic::AtomicIsize;
 use std::sync::atomic::Ordering::SeqCst;
+#[cfg(not(feature = "parking_lot_support"))]
+use std::sync::Mutex;
 
 const NB_BUCKETS: usize = 1 << 12; // 4096
 const BUCKET_MASK: u32 = (1 << 12) - 1;